Bad news for a country with more sheep than humans: out of all the meats, lamb has the worst environmental impact of all.
A colourful report by the US Environmental Working Group suggests lamb, beef and pork generate the most greenhouse gases, use the most fertiliser, water and feed in the production process, and also tend to be higher in fat.
But vegetarians aren't necessarily off the hook; cheese was the third worst polluter, according to the Meat Eater's Guide to Climate Change and Health. Lentils, milk and tomatoes, on the other hand, were the cleanest proteins.
The group assessed 20 types of meat, fish dairy and vegetable proteins to determine their cradle-to-grave carbon footprints, from the fertilisers that
went into growing animal feed, the energy used processing and packing
the meat, and the petrol burned transporting it. It focused on conventional meat only—not organic. It also considered other environmental factors and health considerations.
It also throws up some other interesting calculations. For example, if everyone in the US went meat and dairy-free one day of the week for a year, it would have the same effect as taking 7.6 million cars off the road. And eating just one less burger per week, the report says, is equivalent to driving 500km less.